The present invention relates to processes for packing a drum-shaped electrophotographic photoreceptor for transportation and storage by wrapping its circumferential surface in a packing sheet such as a black paper.
Conventionally, the packing of a drum-shaped electrophotographic photoreceptor for transportation and storage is achieved by wrapping its circumferential surface in a light-shielding packing sheet such as a black paper and further wrapping the packing sheet in a cushioning material.
In recent years, there has occurred image defects due to scratches formed on the surface of an electrophotographic photoreceptor by an edge portion of a packing sheet especially at the time of its unpacking. Such scratches cause black and/or white lines appearing in a formed image on the portions corresponding to the scratches formed on the photoreceptor. This tendency is aggravated, as image forming apparatus such as electrostatic copying machines become downsized and, at the same time, the diameter of electrophotographic photoreceptors installed therein is decreased.
Conventionally, a relatively thick packing sheet has been tightly wrapped the surface of an electrophotographic photoreceptor in order to perfectly shield the photoreceptor from light. However, if an electrophotographic photoreceptor with a smaller diameter is packed in the conventional way, the packing sheet is warped, and an edge portion of the warped packing sheet scratches the surface of the electrophotographic photoreceptor, particularly when it is unpacked.
For example, when an electrophotographic photoreceptor D is unpacked by removing a packing sheet 1' in a circumferential direction of the photoreceptor D as shown by a white arrow in FIG. 3(a), a wrapping-start edge portion 1a' of the packing sheet 1' scratches the surface of the photoreceptor D in a circumferential direction thereof as shown by a black arrow in a fragmentary enlarged view of FIG. 3(a), thereby forming scratches K1 on the surface of the photoreceptor D in a circumferential direction thereof as shown in FIG. 3(b).
When the electrophotographic photoreceptor D is unpacked by drawing out the packing sheet 1' in an axial direction of the photoreceptor D as shown by a white arrow in FIG. 4(a), the wrapping-start edge portion 1a' of the packing sheet 1' scratches the surface of the photoreceptor D along a contact line, thereby forming a scratch K2 on the surface of the photoreceptor D along the contact line as shown in FIG. 4(b).
Such scratches are noticeable in photoreceptors such as selenium-tellurium (Se-Te) photoreceptors and organic photoreceptors, whose surface hardness are relatively low, i.e., a Vicker's hardness of 45 or less.
To solve the above problem, thin sheet materials which are relatively flexible and insusceptible to warping or synthetic papers which are insusceptible to warping may be employed as a packing sheet. However, the former have insufficient light-shielding properties and, therefore, the photosensitivity of the photoreceptor may decrease. The latter mainly comprise a resin, and the resin contains a plasticizer and a residual solvent or the like. Such ingredients may change electric characteristics of the photoreceptor, thus lowing the electric charge characteristics or the photosensitivity.